1. School
of Mathematical and Physical Sciences, University of Newcastle, Callaghan 2308, Australia
2. Institute
of Physics, Poznan University of Technology, 62-965 Poznan, Poland
3. Institute
of Experimental Physics, University of Wroclaw, pl. Maksa Borna 9, 50-204 Wroclaw, Poland
4. London
Centre for Nanotechnology, University College London, London WC1H OAH, U.K.
5. Centre
for Quantum Computation and Communication Technology, School of Physics, The University of Sydney, Sydney, Australia, 2006